<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>

  <form>
    <input type="radio" name="abc" id="gender1" checked> <label for="gender1">男</label>
    <input type="radio" name="abc" id="gender2"> <label for="gender2">女</label>
  </form>

</body>

</html>